| Private investigator | Robert Maheu |
| Client | Sam Giancana |
| Is Current | no |
| Notes | Giancana hired Maheu to spy on his mistress, singer Giancana hired Maheu to spy on his mistress, singer Phyllis McGuire, whom he suspected of having an affair with comedian Dan Rowan., whom he suspected of having an affair with comedian Dan Rowan. |